Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 5: Ultra-fast Phenomena
HL 5.7: Vortrag
Montag, 22. März 2010, 12:00–12:15, H17
Time-resolved photoluminescence from undoped GaAs/ Al0.35Ga0.65As quantum wells quenched by pulsed mid-infrared radiation — •Sabine Zybell1, Harald Schneider1, Martin Wagner1, Stephan Winnerl1, Klaus Köhler2, and Manfred Helm1 — 1Forschungszentrum Dresden-Rossendorf, Dresden, Germany — 2Fraunhofer-Institut für Angewandte Festkörperphysik, Freiburg, Germany
There is much interest in the development of ultrafast devices with possible applications in optoelectronics. An important goal consists in ultrafast control of luminescence in light-emitting devices; it is therefore interesting to investigate the effect of abrupt changes in the carrier distribution on the luminescence signal. We present an experimental study of the effects of mid-infrared radiation (MIR) on the photoluminescence (PL) from undoped AlGaAs/GaAs quantum wells. Electron-hole pairs, created by weak near-infrared light pulses, were excited in the system while a delayed MIR pulse induces an ultrafast redistribution of free carriers that results in abrupt quenching of the PL with a subsequent PL recovery. The source of the MIR laser pulses was the free-electron laser facility FELBE at the Forschungszentrum Dresden-Rossendorf. In combination with the synchroscan streak camera, collecting the PL from the electron-hole recombination, it turned out to be a great spectroscopic tool for time-resolved measurements. Using a simple fit function we found PL recovery times between 40 and 150 ps depending on the MIR intensity.